i'm a noob too, but the low lights ones, generally set the ISO higher and aperture wider (lower f number), so you have have a faster shutter speed. full auto without flash in these situations will usually give you too long of an exposure.

For honest critique, the rest are pretty blah.
I'll go ahead and give you feedback on these, though if you had numbered them it would be a bit easier.

1. White balance seems a bit off, probably because of the candlelight. Also the vent and dog detract from the photo. I think the dog is cute, but if the focus is on the cake then the out of focus puppy competes with/detracts from it a bit.

2. did you shoot this through something? or did you just burn the circle in photoshop? if you PS'ed it I think it would work much better with a less severe (more translucent) burning. If you took it through something I think it might be helpful to be given a bit more of an idea of what you're taking it through. It really doesn't work for me as a whole. Also, again the background (looks like a church) is quite distracting with the pull down projector thing, pulpit etc.

3. Sharp picture, but not really anything exciting? what is the point of this? I dunno... it's not really an abstract, and the shapes aren't really doing anything for me.

4. guitar player... White balance seems off as his head is quite red. also the stuff around his face is quite busy, lots of artifacts to look at. I personally don't think this selective focus works here because the leaves are not something that draws any attention.

5. The child - probably the best, and the main reason for this is that the background is simple. I think the child is underexposed and the white balance is off just a bit, but definitely the best of the set.

6. you're right, you totally blew out their faces.

7. the flash is quite obvious here (generally flash is best if it's not that obvious) but really the composition isn't doing anything for me. It would work to bring back memories, but for me because I don't have memories of the event it doesn't do anything for me. (In my opinion that makes this and others on here a "snapshot")

Generally biggest things to work on I would say are composition (focus on the background, and keeping things simple) and white balance, and practice

umm, as for snapshots and memories, There are many photos that I keep that are snapshots, They bring back memories... no they may not be terribly interesting to others, but if they bring back memories for you then that's great.

To me, a simple background is usually quite safe. There can be stuff in the background, but it's important for that stuff not to distract from what you're focusing on. This is why when you look at well done portraits the background is usually quite simple. This is also why a shallow depth of field (and lenses with great bokeh) are greatly appreciated in portrait photography. These two things make the background rather simple and leave the main focus of the image on the person or people in the image.